The present invention relates generally to rotor spring insulation, and, more particularly, to the prevention of the arcing of electrical current between a rotor connecting rod and a rotor spring in single- and multipole circuit breakers by increasing the amount of insulation on a rotor.
A current-limiting single-pole circuit breaker is generally a high current circuit interrupting device capable of substantially limiting the duration and the intensity of current destined to flow in a circuit experiencing a short circuit fault. To limit the duration and the intensity of short circuit currents, a circuit breaker must, within the shortest possible time, separate its contacts. This separation of the contacts is achieved by rapidly accelerating movable contact arms through an open gap. Upon the intense overcurrent conditions that result in the separation of the contacts, however, arcing often occurs between various parts in the circuit breaker. Arcing between the contacts is usually extinguished by passing the arc through an arc dissipating means. However, arcing may occur between other components of the circuit as well.
Rotary contact arrangements are typically rotatably arranged on a support shaft between the fixed contact arms of the single-pole circuit breaker and function to interrupt the flow of current in the event that a short circuit occurs. A rotary contact arrangement employs a rotor and a pair of rotor springs to maintain contact between the movable contact arms and the fixed contact arms, thus maintaining a good electrical connection between the contacts. The compression forces provided by the rotor springs must be overcome when the contacts become separated and the circuit "blows open" due to the occurrence of opposing electrodynamic repulsion fields between the movable contact aim and the fixed contact arm.
Because of the size restrictions on the sizes of components inside a single-pole circuit breaker casing, the rotor springs are usually situated proximate